Some genes imprint or keep the epigenetic tags during the process of conception. Imprintation occurs in the genes found in the egg and sperm cells before conception occurs. The imprinted gene typically remains active, while the allele that is not imprinted will be inactive. When this process occurs normally, genetic development is typical.
When there is a problem in the inheritance of imprinted genes, significant genetic disorders may result. These can be the result of two active imprinted genes or two inactive imprinted genes. Health issues associated with gene imprintation include cancer and a number of severe health conditions. Diseases directly connected to gene imprinting include Prader-Willi Syndrome and Angelman Disease. Prader-Willi is associated with learning difficulties and uncontrollable eating, while Angelman Disease is linked to learning difficulties and an unusually happy disposition.
Epigenetic information is responsible for many of the challenges associated with cloning mammals. Some scientists believe that gene imprinting is the result of evolutionary competition among males for maternal resources; or the survival of their young over the young of other males.
· LIKELIHOOD OF MUTATIONS
Mutations are changes in the genetic sequence of an organism, and they are a main cause of diversity among organisms, particularly as expressed over time. Most mutations impact the nucleic acids, or acids that form DNA. These changes occur at many different levels, and they can have a range of different consequences. Some of these mutations may be positive or beneficial to the organism. Others may be negative, or damaging to the organism.
For organisms that reproduce, it is essential to classify mutations as heritable, or able to be passed down to the offspring and descendants or not heritable. Mutations that do not impact reproductive cells or hereditary material have little relevance overall, but can be responsible for individual differences. These are called somatic mutations, and do not impact the offspring or descendants of the individual or organism. An albino deer, for example, can be the same as other deer except for color.
· LIKELIHOOD OF MUTATIONS
Mutations are difficult to predict; however, certain types of mutations are more likely than others in some organisms. Mutation rates, overall, are very low–in many cases, mutation does not benefit the organism.
Polygenic inheritance is the interaction of different genes to produce a single phenotype. Skin color is an example of polygenic inheritance. Parents can pass on three different alleles controlling skin color and the amount of melanin present in the skin. In total, six different alleles work together to produce a single phenotype in the individual, or to determine how light or dark the individual’s skin is.
Some diseases are also the result of polygenic inheritance. These are genetic illnesses, apparent at birth. Cleft palate, a deformity in the palate of the mouth that creates an opening between the mouth and sinuses, and spina bifida, a deformity in the spinal development of the fetus, are the result of polygenic inheritance.
Unlike more direct forms of inheritance, environmental issues can directly impact polygenic inheritance. For instance, spina bifida is a neural tube defect. The risk of this defect is lowered if the mother has adequate supplies of folic acid in early pregnancy.
Ecological Systems and Family Functioning
The Ecological Systems Theory, also called the Human Ecology Theory, was formulated by psychologist Urie Bronfenbrenner. This theory addresses the difference between behavior at home, with family, and outside of the family. This theory strives to explain why individuals behave differently with family than they do at work or at school.
There are five environmental systems. Each of these involves different environments encountered during daily life. All environmental systems impact the child and the child’s ongoing development.
The kindergarten classroom is an example of a microsystem
FIVE ENVIRONMENTAL SYSTEMS
Bronfenbrenner and Ecological Systems Theory
Bronfenbrenner believed that the child was at the center of this progressive network of ecosystems, moving further than further out from the child. In order to understand the child’s development, psychologists must consider how the child functions and interacts with each of these individual ecosystems.
SYSTEMS OF A SIX-YEAR-OLD
For a child of six years, microsystems might include home, school, a sports team, and after-school child care. The mesosystem includes the interactions between those different microsystems. The exosystems in the child’s life might include the parents’ workplaces. The macrosystem is the child’s culture, determined by their socioeconomic status, ethnicity and other factors. The chronosystem could be a variety of life events, like the birth of a sibling.